Digital multiplier apparatus



. Feb. 2,' 1960 J. E. SCHULZE 2,923,473

DIGITAL MULTIPLIER APPARATUS Filed Nov 22, 1954 3 Sheets-Sheet 2 III] lllllllll Illllllll lllllllll IIIJIIIII lllllllll lllllllll lllllllll lllllllll a A Lll III I I l I l I II I I I I I II I I I I I I III IIIII I I I I II I I I l l I I I I l I I I I II IIIII I I I I I I l I I llll l I II I l I I I II I I I III FEB 1950 J. SCHULZE 2,923,473

DIGITAL MULTIPLIER APPARATUS Filed Nov. 22, 1954 5 Sheets-Sheet 3 N 1 L I v INVENTOR. Joqah' ICHULZE vYBY DIGITAL MULTIPLIER APPARATUS Joachim Ernst Sclnilze, Oberirohna, near Karl-Marx- Stadt, Germany, assignor to VEB Buchungsm'aschinenwerk Karl-Marx-Stadt, Karl-Marx-Stadt, Germany Application November 22, 1954, Serial No. 470,159

3 Claims. (Cl. Z35161) This invention relates to a control and switching device for electronically controlling and performing cal-.

culations, particularly multiplications. v

The known electronic arrangements of this. class are generally complicated in structure as well as operation. Their control requires for instance a large number of counters consisting of tube systems and devices, in which a series of ten pulses, a second series of nine pulses and an additional series of single pulses, one of which successively occurs after the tenth pulse, have to beissued. Still another pulse is to be applied after 9X9 or 10X 10 2,923,473 I --i atented 2, 1 969 2 currentand when opened show a very high resistance, and because relays may be connected in parallel or in series. The very frequently occurring switching functions for adding'single pulses in multiplication or subtracting them in division are therefore executed by electronic counters 'Which are freeof inertia while the advance of switching of the multiplicand, corresponding to multiplication by ten, is effected by relays. The number of multiplications by ten depends on the number of digits of the multiplier. In case of a four-digit multiplier the multiplicand would 'be multiplied three times'by ten and four relays would do the switching.

" Although the form of construction of the device described with'reference .to the accompanying drawing -relates to the decimal system, the invention is not restricted thereto, but can be applied also to other systems of counting. In the drawing Figure 1 is a diagram of connection for the electronic control-and switching arrangement; i

Fig. 2, a diagram of the sequence of pulses of parts of the same arrangement as shown in Fig. 1 for a hundreds pulses to step up the calculating system for the next cycle and to ascertain the accumulation of pulses in the tube of the next digit of one factor when the product isto be obtained by repeated additions and this feeling out of digits.

This switching of one factor for this ascertaining process as Well as the switching of the multiplicand register to the next place for entering the pulses in thecorrect decadic order is performed in wholy electronically operated machines by means of a considerable number of circuits acting asgates. While this arrangement affords the great advantage of practically timeless switching of counters, 'it is nevertheless expensive and cannot be regarded as 'economic'alin every instance. For example, the electronic tube-controlled calculators provided in connection with ordinary office machines'operate at such a speed-that the results cannot be utilized by them at the same speed. Furthermore, even electronic calculators of this type, which do not operate together with mechanically actuated oflice machines, are not economical, if the entering of the values to be handled by'the calculators takes more time than the actual calculating operation, because high speed calculators cannot carry out more calculations'in a given unit of timethananappliance having a lower calculating speed.

his the object of the invention to provide -a device which is simple to operate and inexpensive. According to the present invention this is accomplished by mouse of t'woidentical left and right side control counters, eachof which is comprised of similar tube counters preferably having a capacity of 10 for operation with the decimal numbering system. These control counters control the feeling out of the multiplier in the multiplier-accumulator; comprisedof tube counters, and the multiplicand in the multiplicand accumulator, also comprised of tube counters. Transfer impulses from the left side control counter simultaneously are, fir'stly, fed into the multiplier accumulator as feeling out impulses to additionally switch it'and thereby releasetransfer impulses over trigger and gatecircuits for feeling out' the multiplicand, secondly serve to further actuate-the right side control counter,- and the invention, since relays'can support a plurality of con 1 {acts which when closdoifer almostnd'resistance to the cycle;

Fig. 3, a diagram of connections of the sequential relay control;

Fig. 4, a'diagram for applying pulses to start electronic control; and Fig.5, a diagram showing the use of a step-by-step relay.

. Multiplication is performed by continuous addition and requires feeling out of the pulses accumulated in the multiplicand and multiplier registers. After the device has been'switched in, the numbers to be worked have to be entered as usual.

The present example will be explained by using a threedigit multiplicand and a four-digit multiplier. Assumed in the multiplicand-register, in decimal counters Z0, Z1 ,and- Z2 operating in the known manner of addition,-the value 354 has been entered, that is to say the counter ,has beenswitched' to 4, the counter Z1 to 5 and the counter Z2 to 73. The multiplier register has four decimal counters Z25, Z26, Z27 and Z28 into which the value 2658 has been entered. The counter Z25 contains the value 8, counter Z26 the value 5, counter Z27'the value 6 and counter Z28 the value 2. These countersmaybe of the type described in US. Patent 2,624,507, columns 8 and 9. Their structure and function are well known and are not to-be explained here in more detail.

When the arrangement is switched on, a pulse generator M is actuated and ina known multivibrator connection continuously gives 01f pulses. The pulse generator M consists in known mannerof two tube systems A and B which-at equal arrangement of both halves of this stopper oscillator alternately give olf pulses, i.e., one pulse from 'one system B is always interposed between two pulses-issued by the other system A, and vice versa. The pulses from system A are applied to gates G0 and G2, and the staggered pulses from system B to gates G3 and G4. These gates are of the type described by C. B. Tompkins and J. Wakelin in their book High Speed Computing Devices (New York 1950) on page 37, chapter 4-3-3. These gates -conduct current only when two positive impulses enter. The term open gate therefore relates-to the condition; wherein the negative bias of a grid-has been lowered so far that an additional single positiveimpulse applied to the gate is permitted to pass. The term closed gate relates to the condition wherein'the grid 'has anegativepotential and a positive impulset'ransmitted to the grid does not release the-flow of current through the gate. Thesegates maybe ofthe sameatype;and-correspond to any known connection. Prior to each calculating cycle actuated at the beginning by a starting pulse and subsequently by a step up pulse a flip-flop or trigger circuit FFO representing one of the I known bistableelectronic connections is-so connected that gate G is closed and thus does not let through pulses a coming from system A. Flip-flop or trigger circuit suitable for the purposes of thepresent invention is described in Radar ElectronicFundamentalsi (Bu'reau o'f' Ships, US. Navy Department, l 946);-p.'1 93 Flip flo'p or trig ger circuits are referred to hereina's fiip-flopsff Further, a flip-flop PM is so connected as to open gate G1 and close gate G2; This arrangement prevents the introduction of pulses issuing from system- A into the connecgee-ans v '7 contact (115 and a negative pulse istransferred over condenser C1 to the delay'trigger VF7.- At the beginning of the second cycle therelay A falls off and thus closes the rest contact a16, the operating contact 1215 being closed also. The condenser C has been charged over the resistance'R between the opening of contact a15 and the tion, sinceboth gates G0, G2 are closed. 'Another flipflop FPS, by its connection, opens gate G4 and closes gate G3, so that the pulses continuously issuing from sys- 'tem B of generator M pass through gate G4over a lead to flip-flops FF10, FF11 and FF12 which are switched from system B are applied also to flip-flop FF5 which is i switched as willbe described later. After-these switching operations pulses supplied by system B effective. v i V I a A product accumulator comprised of tube counters Z to Z16 is connected over contact switches a0 to a2,- b0 to b2, C0 to C2 and d0 to d2, switched by relays ;A, 'B, C

also remain inand D,-with the arrangement over gates G10, G11 and G12. At energization of relay A, for instance, contacts 1 a0, a1 anda2 will therefore be closed, whereby counter Z10 is connected to gate G10, counter Zll to gate G11 and counter Z12 to gate G12. When relay B'is energized,

counter Z11 is connected over contact b0 to gate G10,

so that gatesGlt), G11 and G12 are closed. The pulses 7 closing of contact M5 and isnow discharged once more, whereby another pulse is transferred over condenser C1 to delay trigger VF7. In similar: manner pulses are put out by the relays C and D. I

. The pulse slightly delayed by trigger VF7 then switches flip-flop FFO .tolopen gate G0. The pulses issuingfrom systemA of generator M can now pass throughthe open= gate G0 to the left side control counter Z8 set at 03' The first pulse switches the left side control counter Z8 to l, the second to 2, etc., the tenth to l0 or 0, and this is the first pulse to leave left side control counter Z8, pass to right side control counter Z9 set at 0 and to switch it to 1. At the sametime the pulse coming from Tleft sidecontrol counter Z8 is applied over the opened gate Gl'and contact a8 to the counter'circuit Z25 set at "8 and switches it to 9. During. thefollowing second tens cycle of the pulses issuing from system A the left side counter Z12 over contact'bl to gate G11 and couhtenZlS over contactb2 to'gate 12. 'At energization of relays C or D counters Z12 to Z15 will be connected accordingto the arrangement of contacts c ord. Energizationof a relay, however, does not involve merely the switching of contacts a to be applied to counters Z10 to Z16, bu't'also V of contacts a8 and a9 to d8 and-d9 applied to a multiplier accumulator comprised of tube counters Z to 127;.

For example, at energization of relay A the counter Z25 is connected to thearrangement over contacts as and a9. gate G1 and flip-flop FFl, at energization of relayB the counter Z26 and so forth. It is to be understoodof coursethat' only one relay is energized at'a time.

The relays are controlled. as-follows: V V By the starting contact St,as indicated in Fig. 3, the relay A is pulled up and continues to hold itself over the operating contact 1113, rest 'contacts1'b1'4 and d14. "After.

completion ofthe first electronic cycle of operation a short pulse is applied overthe amplifier RV and energizes relay B over the nowattracted rest contact all. 7 After this pulse has faded out the relay B pulls up and'holds itself over the operating contact b13 and the rest contacts 014 and'dl 4. Simultaneously, therest-contact bM is opened and the energization of relay A falls off.

When the second electronic operating cycle is finished,

the next pulse comes over RV and over the'now closed operating contact 1211 energizes relay C which holds itself control counter Z8 set at OQis stepped up again in the manner describedfland the tenth pulse of this cycle 'switchesleft side control counter Z8 to 10 or "0," where upon likewise a'pulse switches right side control counter :29 from 1- to 2 and counter Z25 from 9" to .10 or 0, so that this counter also supplies a pulse which over closed contact a9 switches flip-fiop FF 1 whereby the gate 'G-1 is closed and gate G2 opened.

, The'counter circuit Z25 has now detenninedthat the. multlplicand 354" has to be added eight times,corre-.

spending to the filling up of the right side control counter 29m 10 or .O. This successiveaddition is controlled by the following pulses issuing from system A offwhich the twenty-first pulse is transferred through gate G0 to left side control counter. Z8 and over gate G2 and a lead to the multiplicand accumulator comprised oftube counters Z0 to Z2. *Bythis pulse the counter Z0 set at 4 'is switched to"5, counter Zl from 5 to 6 and counter 22 from 3 to 4. This twenty-first pulse from systernA 'andfirst pulsev over gate G2 further'switches the opened.

Thepulses from system B pass therefore ,now over gate G3to gates G10,.G11 and G12 which, howevenare still soconnected that theycannotmlet these pulses through. Onlywhen the pulses derived ovferrgate G2 from system A switch the counters Z0, Z1 and Z2 to V 10' or 0 will these counters at different times, accordover operating contact c13 and rest contact d14. By

pulling up relay C the rest contact 014 is opened, so that relay B drops. At the end of the third cycle the operating contact 011 is closed and relay D is energized by the pulse coming from amplifier RVand holds itself over operating contact d13, so that the rest contact (114 is opened and relay C drops.

Whenthe multiplication 1354x2658 is to be performed, the relay-'Ais' energized by the starting pulse, whereby the contacts a0, a1, a2, d8 and a9 are closed and the counter Z10. is connected to gate G10,'counter Z11 to gate G11, counter Z12 to gate G12 and counter Z25 to G12 opened, owing to which the seventh pulse from system B can enter over gate G12v and closed contact a2 ing to their positiomapply a pulse to their subordinated filP-flOPS' FF101to" FF12, whereby they are switched to open the gates G10 to G12, that islto say, the fifth pulse of the third tens cycle switches the counter Z0 to 9,"

counter Z-I to 10 or 0 and counter Z2 to 8. Due to the switching of counter Z1 to .0, theflip-flop .11 is switched and gate G11 opened, so that the fifth pulse of the third tens cycle received from system B is entered over gates'GS and G11and over closed contact a1 into the product counter Zlland sets it from O to l. The sixth pulse from system A of this tenth cycle. sets switched and gate G10 opened and the sixth pulse of this tens cycle from system A enters over gatesG3, G10 and G11 and over closed contacts a0 and a1 intolthe counters Z10 and Z11, setting counter Z10 from70,to,1 and counter Z11 from 1 to 2. The seventh pulse from system A of the third tens cycle sets counter Z2 also at 10 or 0, whereby flip-flop 12 is switched and gate into the counter 212 set at "0" and resetit to 1. Simultaneously, the counter Z10-is set to 2'and counter Z11 t6" 3. Th eighth and. ninth pulse of tens cycle FF3, whereby the gate G4 is closed and gate G3 from sy'stem fB set counter Z-10 to ;4', counter Zl1=to" 5 and counter Z1210 3. The'tenth pulse from system A left side control counter Z8 to 10-or 0, whereby right side control counter Z9 is' set from 2"to 3 and flip- 'fiop 3 switched, so that gate G3 is closed and gate G4 opened with the resultthat the tenth pulse of the third tens cycle from isystemB passes over the opened gate to GI2. .From the thirty-first pulse issuing from system A this switching operation is repeated up :to the hundredth. pulse which is applied'to left side controlcounter Z8 and leaves it as tenth pulse, thereby switching right side control counter Z9 .to 10 or 0, whereby flip-flops '5 and 3 are switched. The pulseissuing from system B after this hundredth pulse passes over gate G4 and switches flip-flops- 10 to'12 as well as flip-flop 5. This the other side of fiip flop actuates the relay control over amplifier RV as stated, and after correspondingamplification of this pulse the relay B is energized, so that the switch'contacts b"are closed, relay 'A falls'ofi and switch contacts a are opened again.

Before starting the second hundreds cycle the counters oc'cupy'the following positions:

'Theimultiplicand registers show again Z0 set to 4, Z1 to 5"and "Z2'to 3. The"multiplier'register shows Z25 set to O, as it has been subjected to the ascertaining operation described, Z26 'se t to 5,"Z27 set to 6 and Z28 set to f2 but the product accumulator, due to .the continuous eightfold addition of the multiplicand register,'conjt'ains the'value 2832,"'sin'ce. the cour'1t'eriZ10 has beenset to "2,"cou'nterZ11' to 3, counter'Z12 to 8 and counter Z13 to 2. Counters Z14 to Z16 are still set to 0. As these product counters are accumulative registers, they apply at a or 0 connection, over a known bufier circuit or the like, a pulse to the next following counter and advance it one place.

After the relays have been switched the initiation of the new hundreds cycle must be slightly delayed by the trigger VF7 to let the relays come to rest when contact chatter has ceased to insure safe passage of the electronic pulses. In order to obtain this delay at the start of the new hundreds cycle, a delay trigger VF7 is provided having the form of a flip-flop capable of operating according to any known retardation connection and returnable to initial position some time after energization. Besides providing the delay trigger VF7 it is necessary to prevent electronic connection in the various counters due to the actuation of the relay contacts. For this reason, all leads without exception, which run over relay contacts, are kept at a predetermined DC. voltage level, so that no jump in the voltage can occur at the closing or opening of contacts. This connection is shown for instance in Fig. l on the lead from gate G10 to counter Z10 and over condensers C1 and C10, which insures D.C.-like blocking, and the predetermined potential is provided over resistances R1, R10. For the sake of greater clearness this connection is shown only once.

The pulse delayed by trigger VF7 switches the flip-flop 0 at the beginning of the new hundreds cycle to open gate G0, whereby pulses from system A can be transferred again over gate G0. The connection operates as described, but the tenth pulse enters through left side control counter Z8 over contact b8 into counter Z26 set to 5 and switches it to 6. The twentieth pulse switches this counter to 7, the thirtieth to 8 the fortieth to 9 and the fiftieth to 10 or 0, so that this counter, over contact b9, supplies a pulse to flip-flop 1, switches it and opens gate G2, whereby the remaining five tens cycles from system A pass over gate G2. The pulses derived from system B after switching flip-flops result "940932-of this multiplication.

" -egsesgavs 10 10- 12 and openin g gates G10 to GIZ-" pass overf'gat'e Gfl0:and contact b0to"counter Z-11 and/ or over gate G11 and 'c t b1"into counter Z13. After the hundred pulsesof thissecondhundreds cycle, owingfto 'the fivefold continuous addition of themultiplicand, the product 'aceumulatorthus holds a value of 20532? :Atthe starting'of the third' hundreds cycle the relay C isenergized and relay B dropped, whereby contactsb are' opened and contacts o closed. After the opening'of gate' G0' always the tenth pulse issuing. from leftside control'counter Z8 enters now counter Z27 over conates then as' stated, and from "the fifth to the tenth tens cycle,.according to position 354 of counters Z0 to Z2, pulses enter over gate G10 and contact c0 into the count- 'er'Z12,'.over gate G11 and contact c2 into counter'Z14,

"so'that' after the hundred pulses of this third hundreds cycle a value of "232932" is contained in the product "accumulator. v To feel out the pulses of the fourth place of the multiplier, that is, of counter Z28, a fourth hundreds cycle has to begin. The relay D 'is energized and relay C drops, whereby contacts 0 are opened again and contacts d closed, so that'counter 228' can be'examined to'find o'utfhowoftenthe multiplicand has to be added over and over again. These controlled pulses enter,'as described, overi'gate' G10 and contact-d0 the counter Z13, over gate G11 and contact d1 counter Z14 andjover gate G12 and contact "d2 counter. Z15and thus represenit the fin'al Insteadfofirelays "A--D a 'step-by-step relay'may' be used) Fig. 5 shows'"h'ow"such a'relay is:to :be interposed in the connection. The insertion of this relay affords,

moreover, the advantage that the sequential control is generator producing a plurality of periodic pulses, a second pulse generator producing pulses alternating with the pulses of said first generator; a plurality of electronic decade counters having pulse responsive inputs, each adapted to recycle upon reaching its digital capacity and emit an output pulse at each recycle; one of said counters being a first control, counter responsive to said first pulse generator; another of said counters being a second control counter identical with said first control counter and connected to said first control counter to respond to recycling pulses of said first control counter; a plurality of gates alternately adjustable between an open position to pass pulses and a closed position adapted to block pulses; a first of said gates operatively connecting the input of said first control counter and said first pulse generator; a plurality of said counters being multiplier counters arranged in an ascending decade order and each adapted to have a digit of a multiplier entered therein, a second of said gates operatively connecting said multiplier counters to the output of said first control counter; trigger means connected to the output of said multiplier counters and to the output of said second control counter and adapted to open said second gate in response to recycling of said multiplier counters and to close said second gate in response-to recycling of said second control counter; switch means actuated in response to the output of said second control counter including a plurality of multiplier switches sequentially connecting said second gate to the output and said trigger means to the input of each of said multipler counters in ascending decade order; a plurality of said counters being multiplicand counters arranged in order of ascending decade power and adapted to have a digit of a multiplicand entered therein; a third ceive transfer pulses from the-"first of said 'control ing one decade of said product counters to said second pulse generator, means for opening each of-said multiplicand gates in response totrecycling of. the correspond- .ing one of said multiplicand counters and closing said gates inresponse to recycling of said first control counter;

a plurality of said switches being ganged product switches initially connecting each of said multiplicand gates to the j product counter decade of corresponding order n and progressively switching each of said multiplicand gate shto the product counter decade of next higher order in response to recycling of said second control counter.

2. A multiplying apparatus as set forth in claim 1 wherein said means for opening and closing s'aidgrnulti 'plicand gates includes a pair of oppositely operative I gates connected to change condition for one pulse duration in response to transfer pulses from said first control counter, one of said pair of gates connecting said second pulse generator to said multiplicand .gates, the' other of. said gates connecting said second pulse generator to'close said i multiplicand gates. t V 7 v r 7 -3. A multiplying apparatus comprising a first pulse ing pulses; apair 10f identical decade control counters connected in'series each operative to recycle and release a transfer pulse upon reaching its digital capacity; a

multiplier register including decade counters arrangedin ascending decade order, a second pulse generator, affirst gate connecting a firstof said control counters to said first pulse generator, a second gate connecting'said'niultigenerator-"for generating asuccession of electrical count- 7 plier register; to said "first control counter,--switch means connecting one of said multiplier-counters to said second gate'andadapted to switch to the counterof next higher decimalorder-in response torecyclingof the second of said p'air Ofi-Cpritl'Ol counters; said second control counter of saidpair oficontrol countersheing connected to recountersj a first trigger circuitfre sponsive to transfer pulsesfrorn said multiplier register; said first trigger being connected to said second gate f ro ening-and closing it, n a third gate responsive to'said first trigger circuit in a sense opposite tosaid second gate; a'multiplicand register including decade counters; said third gate connecting said first pulse generator and said inultiplicand register; a: second trigger connectedto said first pulse generator; a

fourth gate connected ltd said-second triggenrircuit, a fifth gateconnected te -said second trigger circuit; a plurality.of 'rnultiplicand trigger. circuits ,tand gates; con- "nections leading from said second pulsetgenerator to said; fourth and fifth; 'gates' totit'ransfei' pulsesto said 'm'ultiplicand trigger circuits 'and said inultiplicand gates;

connections leading from said niultiplicand register to said multiplicand trigger circuits for switching them; a

product-- accumulating means a including :decade icounters;

connections "fromsaid product accumulating means to said 'inultiplicand gates to receive pulses. frond said second pulse generator; a third trigger circuitysa'idsecond control counter and said third trigger circuit being connected to said first gate fol-disconnectingfirstpulse gen- 'erator; said thirdltrigger being conncrea to said first trigger for closing s'aidfir'stgatt 1 f1 References Cited in the file of this patent i r U STATES P N a: f 2,062,111} Bryce et a1; NGVQ24) 1936 2,624,507 a Phelps 

